The present invention relates to apparatus for stabilizing refuse cans or the like, and method and apparatus for their manufacture. More specifically, a molded concrete base is described, which provides for the vertical stabilization of industrial sized refuse cans, such as those used in parks, against lateral winds and inadvertent spillage. Method and apparatus for the manufacture of such a base also are described, in which a unitary single-cavity, fiberglass mold is flexed to facilitate the stripping of the concrete base therefrom.
Known waste receptacle bases either elaborately are secured to the receptacles, thereby frustrating routine maintenance, or they relatively easily are maintained, but also easily are damaged or dislocated by crosswinds, wildlife or vandals. Illustrative of the former is the base described in U.S. Pat. No. 2,650,786, wherein a stepped, formed concrete structure supports a garbage can and a bolt-mounted, steel frame having a can hold-down assembly. Illustrative of the latter is the base described in U.S. Pat. No. 3,471,114, wherein a ballast-filled, molded, annular base structure grippingly supports a garbage can.
The base described in U.S. Pat. No. 2,650,786 is, in its modified form, a permanent, molded, square, concrete base having a generally cylindrical aperture and an annular, garbage can supporting shoulder. On its rectilinear perimeter, a stepped ledge is equipped with opposite, vertically extending standards which form a heavy steel framework including a handle portion and a horizontal brace that pivotally mounts a garbage can cover hold-down assembly The hold-down assembly permits the lifting of the cover, and also acts to retain the cover in its closed position and the can in its proper upright position. Such modification from a portable hand truck-like device to a permanent garbage can holder requires the substitution of the concrete base for a base plate assembly; the removal of wheels and axle; and the removal of a size adjustable, can gripping band assembly, the last of which is described, in the context of portable can holders, as preventing horizontal and vertical movement of the can relative to the base plate and accommodating conventionally manufactured garbage cans of various diameters and heights.
The base described in U.S. Pat. No. 3,471,114 is size-specific and tapered precisely to conform to the outer surface of the lower portion of a customized garbage container. The lower portion of the container has a bottom that is flanged to provide a horizontal, annular shoulder, which rests on the upper edge of the base to elevate the garbage container above the ground. A bottom wall of the base has an annular recess, located midway between the inner and outer edges, and a threaded passageway that communicates with the base's hollow interior. A threaded plug may be installed and removed from the threaded passageway for filling and emptying the base with ballast, e.g. water or sand. The base is molded of a conformable, presumably polymeric material, which is susceptible of wear, tear, vandalism and spillage of ballast. Because the inner surface of the base is sized and tapered "snugly" to conform to the container, installation and removal of the garbage container requires precise placement and alignment, and even slightly undersized or misshapen containers will not be secured properly to prevent their inadvertent dislocation and potential spillage.
It has been decades since there have been any significant advances in refuse can stabilizing apparatus. Heretofore, it was thought that a compromise was necessary between the seemingly inconsistent goals of security against spillage and facility of use. Even the most advanced prior art apparatus, such as that described by Pratt in U.S. Pat. No. 3,471,114, would require periodic refilling, or topping, of the hollow base with ballast, as the ballast evaporates (water) or settles (sand), and the base described therein provides for the secure stabilization of only those garbage containers having one specific shape and size. It is desirable instead to provide a secure, durable and easy to use stabilizing base for refuse cans and the like, the design of which accommodates the inevitably variant diameters and shapes of the bottoms of conventionally manufactured waste containers of the same, nominal capacity.
A principle object of the invention is to provide a base for a refuse can that vertically stabilizes the can against lateral forces, such as crosswinds, that would upset the can and spill its contents.
Another important object to the invention is to provide a base that, while secure, does not obstruct normal use or normal maintenance, including installation and removal, of the refuse can.
A further, important object of the invention is to provide a base that accommodates refuse cans that vary somewhat in shape or diameter, or that are misshapen by normal use.
Yet another object of the invention is to provide a base that is inexpensive to manufacture, requires little or no maintenance and lasts a long time.
Finally, it is an object of the present invention to provide method and apparatus for manufacturing such a stabilizing base.
In the preferred embodiment of the invention, the stabilizing base takes the form of a unitary, molded, fiber mesh-reinforced concrete annulus dimensioned to extend circumferentially, but loosely, around the bottom portion of a refuse can extending therethrough, and resting therewith on a base supporting surface, e.g. the ground. An inner, substantially right-cylindrical surface of the annulus is dimensioned freely to receive therein a refuse can the bottom portion of which has a diameter within a predefined range of diameters. The base substantially is rounded at the upper vertex of the right triangle, thereby to permit a refuse can easily to be installed therein and removed therefrom and, under the influence of lateral forces such as crosswinds, to rock slightly therealong and better to distribute the load bearing upon the base. The base is sufficiently heavy to provide substantial resistance to crosswinds, and yet is sufficiently light to render the base manually portable. Although the base is of a height that is an insubstantial fraction of the height of the refuse can, it is capable of withstanding substantial crosswinds or other lateral forces, such as a nudge or sideswipe by a foraging animal. The concrete admixture may be color tinted to permit the base either to blend, or to contrast, with its environment.
In a modification to the preferred embodiment, the range of refuse can diameters that securely may be accommodated by the stabilizing base is extended downwardly by increasing the effective height of the base. This increase is effected by providing a right-cylindrical, annular platform on which the base of the preferred embodiment may be stacked. With the combination of the stabilizing base and one or more stackable, elevating platforms, refuse cans manufactured to different nominal dimensions or refuse cans that, with use, have become out-of-round or otherwise misshapen may be accommodated, while maintaining a consistency in the appearance of bases in a variety of applications and settings.
In the preferred method of manufacturing the refuse can stabilizing base of the preferred embodiment, a unitary, single-cavity, fiberglass mold is provided with a generally planar, radially extending, flanged portion on its outer periphery. The mold first is prepared for casting by depositing a release agent along the interior surface that will come into contact with the concrete admixture, and then pouring the concrete admixture into the mold's cavity. What will become the lower outside edge of the base is beveled, e.g. by use of a trowel, to "knock off" what would otherwise be a sharp, annular edge, and the concrete is allowed to moisture-cure to a high strength of approximately 3500 pounds per square inch (PSI). When the mold containing the cured base is inverted onto a flange engaging annular strut, or standoff, of greater inside diameter (ID) than the outside diameter (OD) of the base, the base is stripped from the mold of its own weight. Optionally, the stripping of the base from the mold is facilitated by the application of heat to the outer, annular region of the mold, by the extraction of heat from the inner central region of the mold, or both, thereby flexing the inverted mold convexly downwardly. Such flexing overcomes surface tension between the mating surfaces of the base and the mold along the right-cylindrical inner and frusto-conical outer annular regions.
In use, a refuse can easily may be installed in, or removed from, the base, as the refuse can freely fits within the base. In the presence of crosswinds, or other lateral forces, incident upon the outer surface of the refuse can, the can is permitted to tilt slightly, causing a portion of its bottom lip and a elliptically opposed portion of its lower, outer surface to impinge upon, and thus lock within, the inner annular surface of the base. Because the refuse can rests on the ground, rather than upon an annular shoulder or circular platform as in prior art apparatus, the stabilizing base of the present invention does not permit the accumulation of foreign material between the can and the base providing, in effect, a self-cleaning feature. The density and strength of the fiber mesh-reinforced concrete used to form the stabilizing base and the upper, broadly rounded `edge` of the base minimize, to negligible effect, abrasion between the can and the base, thereby greatly extending the life of both. Finally, the concrete material from which the base is made is virtually impervious to environmental elements or mischief. The straightforward method and apparatus for manufacture, wherein a reusable, flexible, shape-retentive fiberglass mold is used to produce a base easily stripped therefrom, greatly reduce the nonrecurring expense, as well as the unit cost, of manufacture.